Key Takeaways:
- The Last Quarter Moon phase is scheduled for October 12 at 2:13 P.M. EDT.
- On October 12 at 6 P.M. EDT, the Moon will pass 4° north of Jupiter, with Jupiter exhibiting a magnitude of –2.2.
- Telescopic observation of Jupiter before dawn on October 12 will reveal all four Galilean moons: Callisto, Io, Europa, and Ganymede, with specified relative positions.
- The celestial region near Jupiter includes the prominent stars Castor (magnitude 1.6, a telescopic binary) and Pollux (magnitude 1.2, golden yellow) from the constellation Gemini.
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October 12: The Saturn Nebula shines
Last Quarter Moon occurs this afternoon at 2:13 P.M. EDT. A few hours later, the Moon passes 4° north of Jupiter at 6 P.M. EDT. The pair rises around midnight and are visible into the early-morning hours of October 14.
The Moon lies just to the lower left of bright Jupiter; the planet is now magnitude –2.2, the brightest point of light in that region of the sky, far outshining the stars. To Jupiter’s upper left are Castor and Pollux, the brightest stars in Gemini the Twins. Pollux is slightly brighter (magnitude 1.2) and glows a golden yellow. Castor (magnitude 1.6) is a blue-white star that easily splits into two through a telescope, revealing nearly twin stars some 5” apart.
Turning a telescope on Jupiter will show all four of its Galilean moons visible before dawn. Callisto is farthest east, with Io closest to the planet on that side and Europa between them. Ganymede lies alone to Jupiter’s west.
Sunrise: 7:09 A.M.
Sunset: 6:23 P.M.
Moonrise: 11:56 P.M.
Moonset: 2:41 P.M.
Moon Phase: Waning crescent (46%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 10 P.M. local time from the same location.
